Treatment of organic materials



mama June 20, 1939 uurrso STATES rass'rnmm: or oacamo m'rnams No Drawing. Application A r-a2, 1931. Serial 9 Claims.

This invention relates to the saponiflcatlon of organic esters of cellulose,'particularly in the iorm oi filaments, threads, ribbons, iabrics, films and like materials.

U. S. Patent No. 2,091,967, describes a process wherein organic esters of celluloseare saponiiled by organic nitrogenous bases. The bases re- Ierred to are lower aliphatic amines, polymethylene amines tor example cyclohexylamine 10 and heterocyclic bases such as piperidine. Aromatic bases such for example as aniline and the toluidines are not suitable as saponifying agents for organic esters of cellulose.

We have found however that treatment of the material with nitrogenous bases containing aromatic groups afiords strikingly good results provided that the aromatic groups are attached to the nitrogen through aliphatic groups. Thus for example materials of high tenacity, extensibility and elasticity can be obtained by treating filaments, threads and like materials of cellulose acetate or other organic ester of cellulose with benzylamines, and particularly mono-benzylamine. Other bases which can be employed inelude dibenzylamine, trlbenzylamine, monoand dl-c and p-phenyl ethylamines, and quarternary bases containing the benzyl radicle, e. g. benzyl trimethyl ammonium hydroxide. The good results obtainable with the present bases may be due, at least in part, to the very good softening or plasticising properties 01' these bases for the materials under treatment.

The concentration and temperature of the treating medium will depend on the nature of the materials treated and the properties required in the products. Thus for instance, the concen-, tration may range from below 3% to over 30% and the temperature from below 30 C. to above 90 C. It is preferred to work near the lower end of the concentration specified and at relatively high temperatures, e. g. 60-70 or 90 C'. At high concentrations considerable shrinkage can be effected with very little saponiilcation.

The base may be applied by any suitable means. Thus, for example, yarn and like materials may be treated in hank form in a bath of" the treating liquid and allowed to remain therein until the desired saponiflcation is eilected. again, the materials may be drawn continuously through the bath at such a rate that the desired saponiflcation is eflected byv the time the materials; leave the bath. It is of advantage when adopting this method to treat a number oi threads in warp i'ormation, that is in parallel alignment in the same plane. This method facil- In Great Britain April 8, 1936 I itates uniform properties between thread and thread.

The treatment, whether conducted as a continuous operation or as a bath process, may be conducted under pressure, as described in U. 5. application 3. No. 11,080 flledMarch 14, 1935.

By this means higher concentrations of volatile bases and/or higher temperatures may be employed than would otherwise be practicable. When in a continuous process treatment is eifected under pressure a convenient method is to pass the threads through a vessel partly filled with the treating agent, the threads entering and leaving the vessel throughsmall holes above the level of the liquid. To facilitate threading up, the holes are preferably formed in members readily detachable from the apparatus. Thus in one form of apparatus there is at each end oi the 'saporliiying vessel an aperture over which, when the apparatus is in operation, is clamped a detachable perforated plate, the perforations being sufficiently large to take the threads with! out permitting an excessive loss of pressure. Guides or rollers may be provided in the vessel so that the greater part of the path of the materials lies below the level to which the liquid will rise. When working with this type of apparatus in its simplest form, the materials are threaded through the perforations in the one plate, passed under the guides, or rollers, which are conveni ently situated near'the bottom of the vessel, and through the perforations in the other plate. The plates. are then clamped in position and the liquid is run into the vessel up to the required level. Heating coils or other suitable attemperating means are.provided for use when the process is to be carried out at a temperature differing from atmospheric temperature. Ii? the process is to be carried out at a temperature sufilciently high, it may be unnecessary to apply external pressure to the liquid, its own vapour pressure at that temperature being suflicient.

The treatment may be effected under little or no applied tension, so as to facilitate contraction of the materials during saponiflcation. With this in view it is of advantage to provide intermediate rollers which are preierably positively driven at speeds which progressively decrease along the path of the materials. on the other hand, it the bath is such as to exert the necessary softening eiiect upon the materials, they may even be stretched during saponiflcation. Whether the treatment is to be carried out so that the materials contract, or so that they are stretched or so that no lengthening or contraction takes.

place it is of advantage to provide a series of positively driven rollers along the path of the materials, since it is found that such an arrangement leads to great uniformity in the properties of the materials along their length, and particularly uniformity in their tenacity, extension and dyeing properties.

Threading-up of the materials before admission of the treating liquid to the vessel may be avoided by adopting a slightly more elaborate apparatus in which the guides or rollers are attached to a frame so that they can be lifted above the surface of the liquid for threading up and depressed and fixed in position below the surface of the liquid when this has been accomplished.

As indicated above, the treatment may be carried out as a batch process. Thus yarns in bank or other package form, or fabrics, may be suspended within a s'aponifying medium maintained under pressure in a closed vessel. The

pressure may be obtained by any suitable means,

for example by means of pumps or compressors or by means of compressed air. 0n the other hand, as in the continuous process, when a saponifying liquid at a sufliciently high temperature is employed, the vapour pressure of said liquid may be sufficient to provide the necessary pressure, or the pressure may be obtained by introducing a compressed gas into the space above the liquid.

The saponifying bath may contain substances 'adapted to diminish the swelling of the cellulose ester as described in U. S. Patent No. 2,091,972. Among the most useful of such agents are watersolubie salts of organic acids except the soap forming acids and the poly-basic inorganic acids for example the sodium, potassium and ammonium salts of phosphoric acid (except trisodium and tripotassium phosphates), acetic acid, tartaric acid, citric acid, lactic acid, sulphuric acid, thiosulphuric acid and sulphurous acid.

Other suitable swelling repressing agents include the barium, strontium, calcium, magnesium and zinc salts of the organic acids referred to above, the sodium, potassium and ammonium oxalates, sodium and ammonium chloride, sodium, potassium and ammonium formats and the sugars, for example cane sugar, glucose, fructose, mannitol and sorbitol.

The sodium and potassium salts of strong organic acids, such for example as hydrobromic, hydriodic, nitric, perchlorlc and thiocyanic acid, have a tendency to swell the cellulose derivative. This tendency is even more evident in the corresponding strontium, calcium and barium salts. Such salts are not therefore in general suitable as swelling repressing agents. Sodium chloride can however be used and the ammonium salts of all these acids except thiocyanic can also be used. A simple experiment will of course indicate the suitability or unsuitability of any particular substance.

The following examples illustrate the invention:

Example 1 Cellulose acetate yarn of high tenacity in hank form is immersed in a 24% aqueous solution of mono-benzylamine at 60-90 C. until substantially the whole of the acetyl content is removed. The yarn is then removed from the bath, washed and dried.

Example 2 The process is carried out as in Example 1 except that the bath consists of a 1-2% aqueous solution of bensyl trimethyl ammonium hydroxide.

In a similar way other organic bases in which an aromatic group is linked to nitrogen through an aliphatic group can be used, for example dibenzylamine or a-Ol p-mono-phenyl-ethylamine. These bases are used in higher concentration than mono-benzylamlne, the phenyl ethylamines being dissolved in aqueous alcohol and lower temperatures being used, e. g. 25-50" C. The yarn can be treated in the form of a package wound on to a foraminous package carrier instead of in hank form.

Although the invention has been described with particular reference to the saponiflcation of filaments. threads, ribbons, fabrics, films and like materials of cellulose acetate, it is also applicable to the treatment of materials comprising other esters of cellulose, particularly organic esters, l. e. esters containing acidyl groups, for example simple esters such as cellulose formate, propionate or butyrate, ether-esters, such as ethyl cellulose acetate and oxy-ethyl cellulose acetate, and mixed esters, such as cellulose acetate propionate, cellulose acetate-propionate-butyrate and nitrocellulose acetate. The cellulose acetate or other base of which the materials to be treated are made may be of high, medium or low viscosity. For example in the case of cellulose acetate the viscosity may be above 30 to 50 or even 100 or more, measured by comparing the viscosity of a 6% solution of the cellulose acetate in acetone at 25 C. with that of glycerine at the same temperature, taken as 100; or may be considerably lower, for example 10 or to 20, on the same scale.

Materials of high tenacity, which when treated according to the invention give rise to particularly desirable products, may be obtained by processes involving stretching yarns, ribbons or the like considerably at some stage in their manufacture. They may, for example, be stretched considerably during their formation by a wet spinning process such as those described in U. 8. applications 8. Nos. 402,785 filed October 26, 1929, 418,414 filed January 3, 1930, 437,423 filed March 20, 1930 and $69,622 flied July 21, 1930, and Patent No. 2,086,122, or again stretching may be effected as a separate operation subsequent to their production, hot water, steam, or an organic swelling agent or solvent in solution in a non-solvent diluent being used to assist stretching. The materials may have undergone a shrinking operation e. g. after stretching, in which case lower concentrations of the saponifying agent than specified in the examples may be used with advantage.

The degree of saponiflcation effected will depend to some extent upon the object of the process; whether, for example, it is required merely to impart to the materials an affinity for cotton dyes, or to increase their tenacity and/or extensibility to produce materials consisting substantially of regenerated cellulose. The degree of saponification may, for example, reduce the original acid radicle content by 15-20% or less, or may be more extensive involving a reduction of 26 or 30 up to or or from to '75 or or may even effect substantially complete removal of the acid radical groups. The extensibility of high tenacity materials can be enhanced considerably by the process of the invention without substantial saponiilcation, By the process of the invention it is possible to obtain a deep-seated saponiflcation extending to a considerable depth beneath the suriace oi the materials or even throughout substantially the whole section oi the material.

Having described our invention, what we dea sire to secure; by Letters Patent is:

l. Processror the production 0! improved artiflcial materials, which comprises saponiiying tllaments, yarns. ribbons and like materials having a basis oi organic ester oi cellulose, by treat- 10 ment with aqueous solution 0! an organic nitrogenous base in which an aromatic group is linked to the basic nitrogen through an aliphatic smunh 2. Process for the production oi improved arti- 15 iicial materials, which comprises saponiiylng fllaments, yarns. ribbons and like materials having a basis oi cellulose acetate, by treatment with an aqueous solution of an 'organic nitrogenous base in which an aromatic group is linked to the 20 basic nitrogen through an aliphatic group.

3. Process for the production of improved artiiicial materials, which comprises saponiiying fliaments. yarns, ribbons and like materials having a basis of cellulose acetate, by treatment 5 with a liquid comprising monobenzylamine.

4. Process for the production of improved artiiicial which comprises saponifying 11laments. ribbons and like materials having a basis ofgcellulose acetate. by treatment with so a liquid comprising benzyl trimethyl ammonium hydroxide:

5. Process ior the production oi improved artiflcial materials, which comprises saponiiying ill- CERTIFICATE OF Patent No. 2,162,881.

aments, yarns, ribbons and like materials having a basis of cellulose acetate, by treatment with an aqueous solution of monobensylamine.

6. Process for the production of improved artiilcial materials, which comprises saponii'ying filaments, yarns, ribbons and like materials having a basis of cellulose acetate. by treatment with an aqueous solution of benzyl trimethyi ammonium hydroxide.

7. Process for the production of improved artiiicial materials, which comprises saponifying materials which comprise filaments having a basis 01 organic ester of cellulose and having a tenacity oi at least 2.5 grams per denier, by treatment with an aqueous solution 01' an organlc base in which an aromatic group islinked to nitrogen through an aliphatic group.

8. Process for the production of improved artificial materials, which comprises saponifylng maierials which comprise filaments having a basis or organic ester of cellulose and having a tenacity of at least 2.5 grams per denier, by treatment with an aqueous solution of monobenzylamine.

9. Process for the production of improved antmcial materials. which comprises saponiiying materials which comprise filaments having a basis oi cellulose acetate and having a tenacity 0! at least 2.5 grams per denier, by treatment with an aqueous solution of monobenzylamine.

HENRY DREYFUS. ROBERT WIGBTON MONCRIEFF. FRANK BRENT-HALL HILL.

commoner.

HENRY DREYFUS, ET AL. I h

t is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3,

ond column, line 21, claim 8, for the word "or" read of; and that the id Letters Patent should be read with this correction therein that th an may conform to the record of the case in the Patent Office 6 same Signed and sealed this 22nd day of August, A. D. 1959.

(Seal) 1.168111% Frazer Acting Commissioner of Patents.

siderable depth beneath the suriace oi the materials or even throughout substantially the whole section oi the material.

Having described our invention, what we dea sire to secure; by Letters Patent is:

l. Processror the production 0! improved artiflcial materials, which comprises saponiiying tllaments, yarns. ribbons and like materials having a basis oi organic ester oi cellulose, by treat- 10 ment with aqueous solution 0! an organic nitrogenous base in which an aromatic group is linked to the basic nitrogen through an aliphatic smunh 2. Process for the production oi improved arti- 15 iicial materials, which comprises saponiiylng fllaments, yarns. ribbons and like materials having a basis oi cellulose acetate, by treatment with an aqueous solution of an 'organic nitrogenous base in which an aromatic group is linked to the 20 basic nitrogen through an aliphatic group.

3. Process for the production of improved artiiicial materials, which comprises saponiiying fliaments. yarns, ribbons and like materials having a basis of cellulose acetate, by treatment 5 with a liquid comprising monobenzylamine.

4. Process for the production of improved artiiicial which comprises saponifying 11laments. ribbons and like materials having a basis ofgcellulose acetate. by treatment with so a liquid comprising benzyl trimethyl ammonium hydroxide:

5. Process ior the production oi improved artiflcial materials, which comprises saponiiying ill- CERTIFICATE OF Patent No. 2,162,881.

aments, yarns, ribbons and like materials having a basis of cellulose acetate, by treatment with an aqueous solution of monobensylamine.

6. Process for the production of improved artiilcial materials, which comprises saponii'ying filaments, yarns, ribbons and like materials having a basis of cellulose acetate. by treatment with an aqueous solution of benzyl trimethyi ammonium hydroxide.

7. Process for the production of improved artiiicial materials, which comprises saponifying materials which comprise filaments having a basis 01 organic ester of cellulose and having a tenacity oi at least 2.5 grams per denier, by treatment with an aqueous solution 01' an organlc base in which an aromatic group islinked to nitrogen through an aliphatic group.

8. Process for the production of improved artificial materials, which comprises saponifylng maierials which comprise filaments having a basis or organic ester of cellulose and having a tenacity of at least 2.5 grams per denier, by treatment with an aqueous solution of monobenzylamine.

9. Process for the production of improved antmcial materials. which comprises saponiiying materials which comprise filaments having a basis oi cellulose acetate and having a tenacity 0! at least 2.5 grams per denier, by treatment with an aqueous solution of monobenzylamine.

HENRY DREYFUS.

ROBERT WIGETON MONCRIEFF. FRANK BRENT-HALL HILL.

commoner.

HENRY DREYFUS, ET AL. I h

t is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3,

ond column, line 21, claim 8, for the word "or" read of; and that the id Letters Patent should be read with this correction therein that th an may conform to the record of the case in the Patent Office 6 same Signed and sealed this 22nd day of August, A. D. 1959.

(Seal) 1.168111% Frazer Acting Commissioner of Patents. 

